Sounds like you found your own answer - always good. It also sounds like you are testing out the nORMa tool from the logical, rather than conceptual, perspective. That's fine; but the power of the tool and the theory behind it works best starting from the conceptual view. The tool should be able to provide the logical view for you to check over and adjust for physical implementation.
In the ORM designer window, you can add an external uniquenes constraint EUC (from toolbox), between role sequences in multiple Fact Types. If, for example, you want the first and last names of an Employee to be unique, you'd connect the roles for FirstName and LastName value Object Types to the EUC. Here, you'd prohibit hiring a new employee with the same full name, If you want that constraint to be the prefered identifier for Employee, change the property for that EUC.
The idea for doing this at the conceptual level, is that it's easier to see in regular UofD terms; and the tool keeps track of the PKs, FKs for you.
I'd also offer a caveat on looking at RE'ed BDs for examples of how an ORM diagram should look. If you do a few using ORM up front, then RE those, you'll see what I mean. RE has its place, but it has its limitations too.